“Whoa.” Costas put the aquajet in neutral and pointed to the wall on his side. A flight of narrow rock-cut steps led upward to an aperture in the ceiling. “That’s exactly what I’ve been expecting,” he said. “While you had your head down earlier as we were going at full throttle, I saw several small dark openings in the ceiling that must once have been ventilation shafts, long ago blocked by sand and rockfall. This one looks more like a service entrance, something you’d expect partway along a tunnel of this length.” He released the handle of the aquajet, rose to the ceiling, and poked his head into the hole. “No good for us. It’s completely filled with a jumble of rock.”
“You sure?”
“I wouldn’t even want to try. Pulling out one of those rocks might create an instant rockfall and bury us.”
Jack stared at the steps, his mind racing. “I’m thinking of our eleventh-century caliph Al-Hakim. He disappears somewhere around this part of the desert, and then eight hundred years later Corporal Jones reappears after his own little adventure in this place wearing the ring that Howard Carter recognized as the signet of the caliph. Maybe Al-Hakim stumbled across this entrance and literally fell through it. I’m imagining him coming back here again and again, night after night, exploring ever farther into the tunnel, able to do so because the Nile was at low water when he was out here. And then one night he finds something inside, something so revelational that it makes him determined that his next visit will be his last one, that leads him to walk away from his day job once and for all. So he leaves his bloody clothes elsewhere in the desert to suggest that he’s been robbed and murdered, exactly the fate that those around him would have expected for a not very popular caliph wandering alone in the desert at night, and then he comes down here and finds a way of sealing himself inside by triggering a rockfall.”
“If he did that, he might have caused us another problem I’ve just spotted.”
“What do you mean?”
“Take a look ahead.”
Jack turned away from the steps and stared down the tunnel. He finned forward, and out of the darkness his beam began to reflect off irregular rock, quickly revealed as a fallen jumble that blocked the tunnel. It had been their unspoken fear from the outset. Costas powered ahead, leaving Jack with the aquajet, and came to a halt at the top of the pile, where there was a visible crack between the rocks. Costas reached in his arms and pulled, dislodging a block and sliding it out under him. “Watch out,” he exclaimed. The block slid down the pile to the floor, and was followed by several more as he dug his way deeper in. After a few minutes he pulled himself in entirely and disappeared, and then his headlamp beam reversed and shone back at Jack, momentarily dazzling him. “Okay,” Costas said. “If I can get through, then you should have no problem. But I can’t take out anything more. Everything in the jumble below those blocks that I shifted is way too big even to budge.”
Jack swam up to the crack, leaving the aquajet to be pulled through afterward, and eased his way into the hole. Costas was considerably bulkier than Jack was but surprisingly agile, and with his greater length Jack found it difficult to angle himself through the final part of the gap that Costas had created. Finally he was through, and he immediately turned around to retrieve the aquajet, reinserting himself in the crack and reaching for it. He caught hold of one of the handles and pulled it as far as he could, but it quickly became jammed. He pushed himself out and turned to Costas, who was hovering alongside. “I can’t get the aquajet through. There’s absolutely no way. It’s the shield around the propeller.”
Costas pulled himself in the hole to have a look, and he grunted and cursed as he tried every angle. He pushed himself out, breathing noisily. “It was nearly out of juice anyway. It was probably going to give us only another five hundred meters or so.”
“We have another problem. I noticed it only when we slowed down.”
“You mean my leak?”
“It must have been caused by that rockfall that sealed us in at the entrance. There’s a dent in your pack and a stream of bubbles from the manifold. I’d have to remove the cover to take a look.”
“Don’t even try. It might just make it worse. My helmet display told me about it when it happened, but there was nothing I could do about it, and I didn’t see any point in mentioning it. With the aquajet online, I calculated that I should still be able to make the likely length of the tunnel with oxygen to spare.”
“And now?”
“Twenty-five minutes of oxygen left. Almost a kilometer of tunnel. We’re going to be buddy-breathing.”
Jack focused on their training. One of the safety features of the IMU rebreather was an inlet on the manifold that allowed a hose to be attached from another rebreather so that the oxygen supply could be shared. He stared at the manifold, looking for the outlet. He suddenly felt cold in the pit of his stomach. It was gone. He looked quickly around, but he knew he was not going to find it here. There was no way he could attach his hose into Costas’ rebreather now, no way they could share gas. He dropped down alongside Costas and looked at him. “We’re not buddy-breathing. The inlet for the hose is gone. It must have been struck during the rockfall and popped off.”
Costas looked back at him, his face drawn. “I’ve got my portable emergency bottle, and I can use yours. That’s a further ten minutes each.”
“That means having to take off your helmet. Tell me when your carbon dioxide level reaches critical. I won’t be able to help you if you’ve blacked out.”
“Roger that. Let’s go.”
Costas powered ahead again, trailing bubbles behind him. Jack followed, watching his own oxygen consumption rise as he began to exert himself for the first time since entering the tunnel. He was finning hard to keep up. Suddenly everything they had talked about, the prospect of what might lie ahead, was blanked out of his mind, and all he could think about was the next few minutes. It felt horribly like the final countdown of a condemned man. He remembered four days earlier seeing Costas semiconscious in the submersible as he reached it on his free dive, and the huge relief when he had opened up the jammed air valve and seen his revived face at the door of the double-lock chamber. This time there could be no quick solution, no instant reprieve. Once the emergency air had run out, there would be nothing Jack could do except watch Costas drown. If that happened, life as he knew it would be over. Every second now counted.
After fifteen minutes Costas slowed down, his breathing hard and fast. “Okay, Jack. Ten minutes of oxygen left on my readout.”
“Roger that. Less than five hundred meters to go now.” As they swam forward, the tunnel ahead seemed to be surrounded by a golden glow, a ring of shining yellow that separated itself in the center of the tunnel as they came closer. It was a huge torque of gold shimmering in their headlamps, each arm ending at the top in a finial in the shape of a serpent’s head. On either side of it, the tunnel opened out and split into two parallel channels separated by a row of rock-cut columns that extended from the golden ring as far as they could see. “This is what we want,” Jack said, desperately hoping he was right. “This is the beginning of a dock complex that would have allowed barges to arrive on one side while others waited on the opposite side for departure, ready to head back toward the Nile. The wharf can’t be far ahead.”